1. Field of the Invention
The present invention is directed towards a lock assembly comprising a casing means disposed in surrounding and protective relation to each of two lock cylinders. Reinforcing means is integrally formed on the casing and specifically structured and disposed to prevent destruction or collapse of the casing and resulting damage of the lock cylinders and entire lock assembly upon the casing means being subjected to extreme force such as by a hammer or the like.
2. Description of the Prior Art
Both single cylinder and double cylinder dead bolt lock mechanisms have of course been well known in the prior art for many years. Single cylinder dead bolt lock mechanisms which include a thumb turn knob at the side opposite to the cylinder lock are also well known and commercially popular. Conventionally, locks of this type include the extending and retracting of the latch bolt by use of either the lock cylinder or the thumb turn knob. Disadvantages of this type of structure includes the ability to quickly open the lock from the inside merely by operating the thumb turn knob thereby allowing for easy escape. However, double cylinder dead bolt lock structures while overcoming the above type of problem are more expensive.
There is accordingly a demand for a dead bolt type lock mechanism which may be installed on doors or like closure structures and operated by a key from either side of the closure. Prior dead bolt locks are characterized by rim cylinders with exposed or weakly shielded attaching screws. The use of such attaching screws significantly reduces the security of the lock. Also, the rim cylinders employed in prior dead bolt locks also have the deficiency of employing lazy cam tail pieces which are unique to their respective locks and which are often flimsy in their construction.
In order to overcome the above noted problem in the prior art lock mechanisms, efforts should be directed to the provision of reinforcing structure incorporated in the casing means or surrounding casing structures disposed in substantially protecting relation to separate lock cylinders of a double cylinder dead bolt lock structure.